Exp Mol Med.  2004 Apr;36(2):172-178.

Phosphorylation of phospholipase D1 and the modulation of its interaction with RhoA by cAMP-dependent protein kinase

• Jang MJ
• Lee MJ
• Park HY
• Bae YS
• Min DS
• Ryu SH
• Kwak JY

Abstract

Agents that elevate cellular cAMP are known to inhibit the activation of phospholipase D (PLD). We investigated whether PLD can be phosphorylated by cAMP-dependent protein kinase (PKA) and PKA-mediated phosphorylation affects the interaction between PLD and RhoA, a membrane regulator of PLD. PLD1, but not PLD2 was found to be phosphorylated in vivo by the treatment of dibutyryl cAMP (dbcAMP) and in vitro by PKA. PKA inhibitor (KT5720) abolished the dbcAMP-induced phosphorylation of PLD1, but dibutyryl cGMP (dbcGMP) failed to phosphorylate PLD1. The association between PLD1 and Val14RhoA in an immunoprecipitation assay was abolished by both dbcAMP and dbcGMP. Moreover, RhoA but not PLD1 was dissociated from the membrane to the cytosolic fraction in dbcAMP-treated cells. These results suggest that both PLD1 and RhoA are phosphorylated by PKA and the interaction between PLD1 and RhoA is inhibited by the phosphorylation of RhoA rather than by the phosphorylation of PLD1.

Keyword

Phospholipase D; RhoA; cAMP; Protein kinase A; U87 cells

MeSH Terms

Bucladesine/pharmacology
Carbazoles/pharmacology
Cell Line, Tumor
Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors/*metabolism
Dibutyryl Cyclic GMP/pharmacology
Enzyme Inhibitors/pharmacology
Humans
Indoles/pharmacology
Phospholipase D/*metabolism
Phosphorylation/drug effects
Pyrroles/pharmacology
Research Support, Non-U.S. Gov't
rhoA GTP-Binding Protein/*metabolism